walkable displacements in hammer

Having mapped for several years using hammer and it's predecessor's i havn't really been inclined to research anything new about it, as everything i currently know gets me by quite efficiently. Some of the newer mappers (and i am only embarresing myself infront of them) may already be aware of this function, having bumped into it whilst reading more up to date tutorials than i have.

Anyway, boasting about my years of experience (that have come to little) aside. I discovered this neat little toggle button. I wont elaborate anymore as the image is quite self explanitory. (Also note, the fade prediction button for models, 4 buttons over to the right).

Normally a mapper may never encounter/produce a situation where there is a displacement at such acute angles which a player is supposed to climb (as it normally looks terrible ugly) but for those who do..